Field of the Invention
Embodiments of the present invention generally relate to a display device, and more particularly, to an array substrate for a display device, the display device comprising the array substrate and a method for manufacturing the array substrate.
Description of the Related Art
Display modes of a TFT-LCD (Thin Film Transistor-Liquid Crystal Display) mainly comprise TN (Twist Nematic), VA (Vertical Align), IPS (In Plane Switch) and the like, wherein VA and IPS belongs to the current mainstream of wide visual angle and basically solve problems of narrow visual angle and serious grayscale inversion in TN mode.
A multi-dimensional electrical field is formed through an electrical field generated at edges of slit pixel electrodes and an electrical field generated between a slit pixel electrode layer and a plate common electrode layer in the same plane based on an ADSDS (Advanced Super Dimension Switch) technique, so that all of aligned liquid crystal molecules between the slit pixel electrodes and directly above the slit pixel electrodes in a liquid crystal cell are driven to deflect, thereby improving operating efficiency of the liquid crystal molecules and increasing light transmittance. It is possible to improve quality of images of TFT-LCD products by using the Advanced Super Dimension Switch technique, so that the TFT-LCD has advantages of high resolution, high transmittance, low power consumption, wide visual angle, high aperture ratio, low chromatic aberration, no Push Mura and so on.
With the continuous improvement of resolution of the TFT-LCD products, a pixel is more and more small in size, and requirements on an aperture ratio of the pixel are more and more high. Thus, a width of a black matrix should be minimized as soon as possible. At the same time, since a common electrode of the ASDS product is generally made of indium tin oxide ITO having a relatively high resistance. In order to reduce RC delay and increase storage capacitance, an area of the common electrode will be increased as soon as possible when designing the common electrode, so that the ITO and a data line are generally designed to be overlapped with each other.
As illustrated in FIGS. 1 and 2, an existing ADSDS product with a high resolution comprises an array substrate and a color filter substrate. The array substrate includes a first layer ITO used as a common electrode 14′, a second layer ITO used as a pixel electrode 16′, an insulating layer between the common electrode 14′ and the pixel electrode 16′, and a metal data line 12′. The color filter substrate includes a plurality of black matrixes 22′, a plurality of sub-pixel units 231′/232′ and an organic planarization layer 24′. Each of the sub-pixel units generally comprises sub-pixel units of red, green and blue. The black matrixes 22′ is disposed between the respective sub-pixel units 231′ and 232′ with the black matrix being located above the metal data line 12′.
FIG. 2 is a schematic cross-sectional view of the ADSDS product as shown in Figure taken along a direction A-B in which all of an organic planarization layer 13′, the black matrixes 22′, the sub-pixel units 231′ and 232′ and the organic planarization layer 24′may be made of resin materials, and the insulating layer 15′ may be made of silicon nitride material. A liquid crystal layer 31′ is located between the array substrate and the color filter substrate. When no electrical field is applied, liquid crystal molecules in the liquid crystal layer 31′ will not be deflected and no lights are emitted from a display panel so that the display panel is in a black state. When a data voltage is applied to the sub-pixel units, the ITO pixel electrode and the ITO common electrode generate a fringe field 32′, and the liquid crystal molecules in regions affected by the fringe field 32′ will be deflected, such that an incident backlight 11′ is formed as an emergent light 21′ on one side of the color filter substrate after passing through the array substrate.
As shown in FIG. 3, since a width of the black matrix of the ADSDS product with high resolution is generally less than 6.0 μm, an overlapping width of the black matrix and the data line is small. If one side of the black matrix is shifted when the color filter is assembled with the array substrate, the fringe electrical field formed by the ITO of the pixel electrode and the ITO of the common electrode would be close to or even beyond the other side of the black matrix, i.e., a range of the liquid crystal layer which is deflected would be closed to or even beyond the other side of the black matrix. When a LCD separately displays red, green and blue images, i.e. the first sub-pixel unit 231′ is applied with the data voltage and the adjacent sub-pixel unit 232′ is not applied with the data voltage, minor emergent lights 25′ would be generated on the other side of the black matrix close to the adjacent sub-pixel unit 232′ in addition to the emergent light 21′ of the first sub-pixel unit 231′. Therefore, the monochromatic emergent light such as red light of the first sub-pixel unit 231′ is prone to be mixed with the monochromatic emergent light such as green light of the adjacent sub-pixel unit 232′ to generate a mixed light such as yellow light and this issue will be more serious in a case of side visual angle.